The present invention relates to the improvement of a starter switch for a fluorescent lamp, and in particular, relates to such a starter switch which fires a fluorescent lamp very quickly.
Generally, a fluorescent lamp system, a sodium lamp system or a mercury lamp system, has a discharge lamp 1 with a pair of hot cathodes 1a and 1b, a ballast 2 which is implemented by an inductor for providing the high firing voltage for starting a discharge lamp and restricting a discharge current after fired, and a glow switch G with a bimetal. In that conventional fluorescent lamp system, when a switch SW is turned ON, a circuit through a ballast 2, a pair of cathodes 1a and 1b of a fluorescent lamp 1 and a glow switch G is completed, and an electric current flows in that circuit. Thus, the hot cathodes 1a and 1b are heated. Then, said glow switch G is switched OFF. Due to the sudden switching OFF of the current by the glow switch, the inductor 2 generates the high voltage which fires the lamp 1. When the discharge of the lamp starts, the current in the lamp is restricted by the inductor 2.
However, a conventional fluorescent lamp system has the disadvantages that it takes long to start the discharge of a fluorescent lamp. Usually, it takes more than three seconds to lighting a lamp after a switch is turned ON. Therefore, a quick start lamp which lights just when a switch is turned ON has been requested. Another disadvantage of a conventional fluorescent lamp is the presence of a glow switch, which has a bimetal. Due to the presence of a bimetal which has a metal contact, the life time of that contact is not long, and we must change a glow switch often.
Some proposals for overcoming said disadvantages of a conventional fluorescent lamp have been known, and a quick start fluorescent lamp, a rapid start fluorescent lamp or an instant start fluorescent lamp have been known. However, those quick start type fluorescent lamps have the disadvantage that the particular structure of a lamp must be utilized. Therefore, those proposals can not shorten the start time of a conventional glow switch type fluorescent lamp.